Ready-to-eat foods are often cooked by boiling or frying in the presence of fats and oils. These foods may be prepared in larger industrial cooking appliances which cannot be disassembled to clean. Removal of soils from surfaces of industrial cooking appliances can be difficult, especially if the soils originate from an animal or vegetable source, such as charred animal or vegetable fats, fatty derivatives and other organic deposits.
Cleaning these surfaces has been a vexing problem in industries such as the food preparation industry, where essentially complete cleaning of such surfaces is desirable. For example, in industrial production plants, stainless steel cooking surfaces may be found in food fryers which are heated to high temperatures for the cooking of large amounts of food.
Soiling matter deposited on these surfaces may consist of a complex mixture of natural fats, fatty derivatives and other organic deposits from the cooking of food. During heating at high temperatures subsequent to deposition, this soiling matter may be converted into a charred, polymeric mass which is difficult to remove and which can comprise complex hydrocarbon chains containing fatty ester groups and ether linkages.
Removal of these soils from food fryers has customarily been accomplished by a process known in the industry as a "boil-out," which typically involves adding aqueous solution of a cleaner to a fryer, bringing the fryer to an elevated temperature, such as the boiling point of the cleaner, and maintaining the elevated temperature for a given period of time.
In the past, traditional cleaning methods have used high concentrations of caustic soda or caustic pot ash to saponify normal fat-based oils such as triglycerides used in processes such as deep fat frying. These oils are typically cottonseed or soybean oils. The saponification process breaks the triglycerides into their more soluble component fatty acids and glycerin.
Conventional cleaning compositions known previously include Hammerel, U.S. Pat. No. 4,158,644 which discloses a composition of quaternary ammonium salt, betaine, and nonionic surfactant. Hammer et. al. discloses the use of an aqueous composition containing these three surfactants and cleaning various fats and greases such as crankcase oil from hard surfaces.
Wise et. al. U.S. Pat. No. 4,176,080 discloses a detergent composition for oily soil removal from laundered dry goods. The Wise et. al. composition contains a water insoluble solvent with a water and oil emulsifier and a discrete amount of solvent stripping agent.
Flanagan, U.S. Pat. No. 4,264,479 discloses a generic composition of nonionic, amine oxide, and quaternary ammonium compound which may be mixed with certain chelating agents and sodium hydroxide to degrease and clean wax, soap, and other soils from hard surfaces.
However, modern trends towards healthier foods and, in turn, reduced caloric content, have resulted in the use of materials which provide reduced caloric content while maintaining the organoleptic properties of the food but which also create additional problems in cleaning food preparation surfaces.
For example, sucrose polyesters such as those disclosed in Jandeseck et. al., U.S. Pat. No. 4,797,300, Jandeseck et. al., U.S. Pat. No. 5,017,398, Spinner et. al., U.S. Pat. No. 4,948,811, Jandeseck, U.S. Pat. No. 3,865,939, Jandeseck, U.S. Pat. No. 4,005,195, Jandeseck et. al., U.S. Pat. No. 4,005,196, Jandeseck U.S. Pat. No. 4,264,583, and Volpingheim et. al., U.S. Pat. No. 4,241,054, all of which are incorporated herein by reference, have added benefits in reducing the caloric content of food while maintaining certain organoleptic properties.
Generally, the sucrose polyester is a sucrose molecule reacted with a fatty acid ester comprising anywhere from 6 to 8 carbons. The resultant molecule is large and stearically hindered. The stearic hindrance greatly slows the saponification making the cleaning process less efficient when traditional methods and compositions are used.
With traditional fryer cleaning solutions, the sucrose polyester generally does not emulsify or suspend in the cleaning solution. Rather, the sucrose polyester has a tendency to form a hard waxy film on the surface which is treated. Further, the removal of triglyceride oils and fats which have been carbonized, gelled, crosslinked or otherwise congealed have also presented a continuing problem in the cleaning of food preparation surfaces.
As a result, there is a need for compositions and methods which clean oily soils comprising sucrose polyesters from food preparation surfaces.